It is important to raise or lower the height of the seat for enhancing the occupant's comfort. There are various types of seat lifting assemblies available in the market which raise or lower the height of the seat by means of movement of lifting means. Seat lifting assemblies as described by the prior art have many disadvantages. The major disadvantage is that either the seat takes a long series of steps to reach the highest or the lowest position or moves in one step by the air pressure or by force of weight.
The seats which take a number of steps in reaching a particular position move with respect to the angular movement of the lifting means. The angular movement of lifting means is directly proportional to the height gained or lost by the seat. The seat lifting assemblies described in prior art have a lower range of value for the constant in said directly proportional equation. As a result, such types of seat lifting assemblies take unnecessarily longer time to reach a particular position and requires more manual labour.
The seats which move upward or downward in one step, do not quite reach the exact desired position easily. Thereby, increasing the number of steps required to reach the desired position.
One of the prior art U.S. Pat. No. 6,422,651 B1 describes a seat lifting assembly wherein the seat moves upward in a number of steps but comes down in lesser steps as greater angular freedom is provided to the lifting means. Now the need has aroused to develop such a seat lifting assembly where lesser angular movement of the lifting means provides larger increase or decrease in the height of the seat.
The present invention provides a seat lifting assembly having a lifting means, an assembly of gears, arrangement of shafts and link which provides higher movement to seat with respect to smaller angular movement of lifting means.